1. Technical Field
The present invention relates to an adjuster that may be mounted on a tailpiece of a string instrument and that facilitates tuning of very small pitches.
2. Background Art
String instruments such as violins, violas, cellos, etc., have pegs for tightening and loosening strings for tuning. In addition, there may be cases in which tuning devices called “adjusters” are used in order to finely adjust very small pitches. The adjusters are used for tuning from a back end side of the strings that is an opposite side of the pegs. This kind of adjuster is specifically often used for the thinnest string (a first string in a case of a violin) and is mounted on a tailpiece that is fixed to a back end portion of a body of the string instrument. As a conventional adjuster, an adjuster of ball-end type is disclosed in Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2007-513359, for example.
FIG. 6 shows a tailpiece of an ordinary violin. The tailpiece 6 has a front end portion (right end portion in FIG. 6) for stretching four strings, and the front end portion is formed with anchor holes 11 for anchoring back ends of the strings. The anchor hole 11 is made by forming a circular hole 11a at the back of a slit 11b that extends in the front-back direction. The circular hole 11a allows a ball to pass therethrough. The slit 11b allows the string to pass therethrough. The string has a ball that is fixed at the back end. The string is passed through the slit 11b by passing the ball through the hole 11a from a surface side, and the string passed through the slit 11b is stretched forward. Thus, the string is provided with tension.
FIGS. 7A and 7B show one of the adjuster of ball-end type. This adjuster has a frame 101 extending in the front-back direction. The frame 101 has a back end (left end in FIGS. 7A and 7B) provided with a cylindrical screw portion 102. The screw portion 102 is formed with threads at an outer circumferential surface and at an inner circumferential surface and extends upwardly. The screw portion 102 is passed through the hole 11a from a back side (lower side in FIGS. 7A and 7B) of the tailpiece 6, and the screw portion 102 projecting from the tailpiece 6 is screwed with a nut 103. Thus, the adjuster is fixed to the tailpiece 6. The frame 101 abuts on the back surface of the tailpiece 6 and has a front end portion that projects forward from a front end edge of the tailpiece 6. The front end portion of the frame 101 supports an L-shaped lever 105 via a pin 106 so that the lever 105 is swingable in a direction indicated by an arrow H. The lever 105 has a hook portion 104 by which a string 8 is anchored with a ball 200. The hook portion 104 is formed with a slit 104a that opens upwardly so as to allow the string 8 to pass through. An adjusting screw 107 is screwed into the screw hole inside the screw portion 102. The adjusting screw 107 abuts on a back end of the lever 105, and the lever 105 swings according to a screwed amount of the adjusting screw 107, whereby tuning is performed.
On the other hand, FIGS. 8A and 8B show an adjuster of another type. This tuning device is called an “adjuster of the loop-end type” and basically has the same structure as that of an adjuster of the ball-end type. That is, the adjuster has a frame 111 provided with a screw portion 112. The screw portion 112 is passed through the hole 11a from the back side of the tailpiece 6 and is screwed with a nut 113. An adjusting screw 117 is screwed into a screw hole inside the screw portion 112 and swings a lever 115. The lever 115 is swingably supported via a pin 116 by the frame 111 and has a hook portion 114. In this case, the lever 115 swings within the slit 11b, which is different from the structure of the adjuster of ball-end type. Moreover, the hook portion 114 is close to the nut 113, whereby there is no space for the ball. Therefore, a looped back end of the string 8 is anchored to the hook portion 14.
In the adjuster of the ball-end type shown in FIGS. 7A and 7B, the lever 105 is relatively long, and the string 8 is tightened by pressing the back end portion of the lever 105. Therefore, only a small controlling force is required, and tuning is easily performed. Nevertheless, since the hook portion 104 is arranged forward from the front end edge of the tailpiece 6, the total length of the string 8 is short. For example, in a case of using the adjuster for one string, balance of musical sounds of the string with other strings is difficult to control. In addition, a backward extra string between the back end of the string 8 and a bridge (9b in FIG. 2) has a length that is greatly different from those of the other strings. Accordingly, musical performance such as afterglow of musical sounds may be affected by the backward extra strings.
In contrast, in the adjuster of the loop-end type shown in FIGS. 8A and 8B, since the hook portion 114 is arranged over the anchor hole 11, the length of the string 8 is not much different from those of the other strings. However, the lever 115 is relatively short, and thereby large controlling force is required. In addition, the lever 115 swings in a relatively small range. Accordingly, tuning is not easily performed.
In each of the adjusters of the ball-end type and the loop-end type, the lever 105 (115) is swung by the adjusting screw 107 (117) that passes through the hole 11a. Since the lever is made to be pressed by the adjusting screw, a space between the lever and a body surface of the string instrument is small. Accordingly, the swing range of the lever, that is, the tuning range, is limited.